This invention relates to a blast shelter and more particularly to a personal blast shelter capable of providing improved protection during and after the detonation of nuclear weapons.
In spite of a large amount of misinformation which has been presented to the public, there is convincing scientific and technical information available that it is possible for most people to survive on both a short and long term basis a full scale exchange of nuclear weapons provided that proper advance preparations are made.
It is acknowledged that it would be a moot point that an individual survive such a nuclear holocaust if as a result all life on earth were doomed to extinction or marginal existence. However, in 1975 and 1985 the National Academy of Sciences (NAS) produced extensive reports on the atmospheric effects from various war scenarios which contradict any such idea. In the 1975 report, NAS envisioned an exchange of 550 to 1000 weapons with a yield of 20 megatons (MT) as surface bursts and the simultaneous detonations of 4000 to 5000 weapons of 1 to 2 MT yield also detonated as surface bursts. In the 1985 report, the scenario suggested that about 6500, or one half the world arsenal, would be detonated, of which 1500 MT would be detonated at ground level and the other 5000 MT at altitudes chosen so as to maximize blast damage to structures. Targets for the above detonations would not only include those purely of a strategic nature such as missile silos, strategic air forces, key military bases, etc., but also manufacturing and electric power plants, petroleum refineries, and other targets associated with large urban areas, so it has to be presumed that all major cities in the United States would be targeted.
Careful analysis presented in the above reports and other information of a scientific and technical nature which is available show that the results of such detonations can be divided into immediate and longer time effects, and that these effects can be further divided into discrete and readily quantifiable conditions which can be dealt with effectively to insure long term survivability of the individual and the community.
Attempts up to now to produce shelters capable of providing such survival have unfortunately been inhibited by the growth of myths surrounding the results of a nuclear war. For example, in a book entitled "Nuclear Madness", the author states "A 1000 megaton device exploded in outer space could devastate an area the size of the western states". There are no weapons in existence even the size of 100 MT, and it is not conceivable based upon the potential effectiveness of such a weapon that one of that size would even be built. The scientific fact is that when weapon yield increases by a factor of 10, the danger radius only doubles. A 100 MT device would only have a danger radius twice that of a 10 MT weapon. Consequently, due to the law of diminishing returns on bomb size, it is seen that there are practical limits on bomb size and this is a major factor which indicates that it is possible to produce a shelter which is effective regardless of bomb size, provided certain other problems can be solved.
In a book entitled "Freeze", the statement is made "No previous war, no volcano, no earthquake, no plague has ever posed the type of threat to our civilization and our planet as does a general nuclear war". The bubonic plague killed over 25 million people, about 25 percent of the population of Europe. There were more dead bodies than the living could bury. In World War II, over 1700 Soviet cities were destroyed with over 20 million people. In addition, the earth has suffered major famines in which large portions of the population died, as for example, 20 million Russians in 1920 and 50 million Chinese in the period between 1848 and 1864. In fact, the state of technology today is such that the human population is much better equipped to meet the calamity of a nuclear war than the populations which suffered the disasters noted above.
In reality, the question today is not whether persons can survive a nuclear holocaust but whether people have the will and determination to prepare for survival.
Some efforts have been made to prepare shelters capable of providing some degree of protection in the event of a nuclear blast or multiple detonations. Basically, most such shelters have been designed to afford a measure of protection from fallout. However, the fallout shelter provides no blast protection, nor will it give any protection against any number of certain other surface effects, such as, a burst of nuclear radiation, the fireball which can reach millions of degrees Fahrenheit, thermal radiation which is heat transmitted from the fireball, fire storms produced by the thermal radiation, pressure waves (both under and over pressure), and blast wind.
During the first minute after detonation of a nuclear weapon, there will be a burst of radiation in which neutrons and gamma rays are of main concern. The intensity of this radiation drops off rapidly with distance from ground zero, and at a distance of four miles the total dose is virtually zero for any size weapon up to 20 MT. In addition, the gamma radiation is reduced by a factor of 1000 in passing through 55 inches of earth, while for neutron radiation this reduction takes place in 47 inches of earth.
The fireball, which lasts for less than 90 seconds, reaches temperature levels millions of degrees Fahrenheit. The radius of the fireball is up to 2.2 miles for a 20 MT weapon detonated in an air burst and 3.0 miles in a surface burst. It is anticipated that an underground shelter not within the radius of the fireball will survive the fireball if properly designed.
Thermal radiation is felt as heat resulting from the fireball. Thermal radiation, which will ignite combustible material withn a limited distance from ground zero, drops off rapidly with distance and is further attenuated by the scattering effect of the atmosphere. This radiation travels at the speed of light so that it appears virtually instantaneously. The fires caused by the thermal radiation do continue for a significant period of time and a properly designed shelter should be able to accommodate such a condition on the ground surface.
The effect of the blast itself is to produce shock or pressure waves followed by a blast wind. These destructive forces damage or destroy surface structures to a degree depending on size of the weapon, distance from ground zero, and the type of construction. In the case of an underground shelter, the effect of principal concern is that due to increases and decreases in pressure since all shelters have some communication with ground level and there will be a transfer of forces to the shelter structure and to the persons within the shelter. For example, overpressure can cause rupture of ears, lungs, and stomach, and an air embolism in the heart and brain. It is thus essential for the shelter to protect the occupants from such effects.
The fallout is dirt and debris from the crater of a nuclear explosion which enters the fireball and is fused, vaporized and made radioactive. It is then drawn up into the stem of the mushroom cloud and reaches a high altitude and soon begins to fall back to earth as "fallout". The shelter must protect its occupants from the radioactive components of the fallout.
A hopeful fact when considering the effects of fallout is that the basic requirements for human survival, namely, water, air and food cannot themselves become radioactive from fallout. These essential elements can and do become contaminated with radioactive impurities which, however, can be removed.
Some back yard, underground shelters have been developed, but they lack adequate protection against the effects of nuclear weapons as described above plus protection against intruders. The latter is likely to be a severe problem in the event of a nuclear exchange and must be taken into account in any proper shelter design.
The back yard, or personal, shelter has the capability of providing shelter for a small number of people, such as a family unit and incorporates features to protect its occupants against the effects of nuclear weapons. But provision must also be made for taking in air and venting, and permitting access to the shelter. However, vents and access ports make it possible for intruders to flush out the occupants with the use of gasoline, water, fire, etc., as well as perhaps using a vehicle to force open the hatch. Current shelter designs do not give adequate attention to this aspect of the problem.